This invention relates to electrosurgical instruments and, more particularly, it is directed to improvements in the switching mechanism, generator connector and the general assembly of the instrument.
A field of medical instrumentation that has grown rapidly in recent years is electrosurgery, in which a suitable generator provides a high frequency, high voltage current which is transmitted to a small surgical electrode having an appropriate configuration for application to a patient. The patient normally is connected to a grounding plate or pad which is connected by a further conductor back to the generator. The relatively small area of contact by the electrode with the patient provides intense current in a highly localized area, producing a cutting action. The current passes through the patients body to the patient pad or plate where the area of contact is so great that no burning effect occurs.
For cutting purposes, the generator is activated to produce a continuous sine wave signal; however, the same instrument may be applied to the wound after cutting in order to produce coagulation. For this purpose the generator may be selectively activated to produce a pulsing signal which produces the desired results. A switching mechanism is available for the operator to selectively control an activating means for causing the generator to produce the desired type of current.
Although a number of arrangements have been devised for selectively activating the pulsing signal, the most satisfactory of these arrangements is a multiple wire cable conductor extending from the generator to the electrode holder. One conductor is normally connected to the electrode to carry the therapeutic current and two other conductors are selectively connectible to the therapeutic current conductor through switches to complete circuits back to the activating means for causing the generator to produce the desired mode of current. Previously available devices have provided mechanisms for supporting and positioning the wires of the multiple wire cable so that they could be connected to their respective electrodes or switches; however, the wire conductor support and positioning means have had many disadvantages in that the connections were expensive to achieve and failed to provide a positive connection. Furthermore, prior devices provided generator connectors at the proximal end of the multiple wire cable that created wear problems on the connector receptacles of the various generators with which the electrosurgical instrument was used. This condition was created primarily because of narrow lineal contact between the previous connectors and the connector receptacles of the generators.